In my opinion, all these spirits can not move, transfer, remove or give anything underneath the soil to anybody.
My logic goes like this:
1. If a man was killed and burried together with the treasure, the first thing he will do if his awareness comes back, is to 'move' his burried body to the top, and I haven't heard or seen anything like that in my whole life, what is more about treasure?
2. If another spirit is guarding the treasure and 'befriend' a living such as medium, psychic or whatever, there is a possibility that he will give it to his new found 'friend' instead to anybody who is only a friend of his 'friend'. But I haven't seen any 'living friend' of any spirit who become rich because of the treasure which was given to him by any spirit.
3. If the 'spirits' have the power to give the treasure to those who have 'pure hearts', how come those who have dirty hearts gets the treasure and 'kill' the men with pure heart?
In my opinion, if these spirits really exist and can do anything over the living, what they can do is to disturb and distort our own 'spirit' and mislead our minds so that it will lose whatever faith, logic and knowledge we have.
We 'coined' every unusual things that happen in any treasure projects as work of 'guardian spirits' which in my opinion can be explained scientifically and logically.
Or can we say that these 'spirits' are used as "scapegoat" if one's project fails?